1. Field of the Invention
The present invention relates to a certifying system using a radio tag, a radio tag, a certifying method and a certifying program.
2. Description of Related Art
Heretofore, in a security system for permitting unlocking of a door, a log-in and the like to a PC (personal computer) by executing certification, a technique is well-known for using an ID (identification) card at the time of certification by previously writing information for taking a permission of the certification on the ID card.
If the above-mentioned ID card, on which the information and the like for taking the permission of the certification is written, is handed over to another person as a result of a theft and the like, it is possible for the ID card to be simply abused by the another person. Further, as long as the theft of the ID card is not discovered, there is a possibility that the ID card is being continuously abused for a long period.
When the theft of the ID card is discovered, it is necessary that the theft of the ID card is registered on a system for certifying according to the ID card and that the certification according to the stolen ID card is prohibited. Thus, this requirement increases the number of man-hours required for managing the security system.